Semiconductor or integrated circuit (IC) fabrication techniques utilize equipment which must be cleaned of contaminants. In one example, the fabrication of germanium-containing ICs utilizing strained silicon (SMOS) can contaminate IC fabrication equipment or processing tools. The downtime or maintenance time associated with fabrication equipment is extended due to germanium contamination. Once the equipment is cleaned or decontaminated, the equipment can be utilized to continue to manufacture or fabricate ICs.
In conventional SMOS processes, germanium is implanted, deposited, or otherwise provided to silicon layers to change the lattice structure of the silicon and increase carrier mobility. IC fabrication equipment that tends to become contaminated with germanium can include deposition chambers, furnaces, diffusion equipment, etching tools, etc. The quartzware associated with such equipment is typically susceptible to germanium contamination.
Germanium contamination is becoming a more serious issue as IC fabrication processes explore the advantages of the higher carrier mobility of strained silicon (SMOS) devices. Germanium contamination is particularly problematic when equipment is used in both non-germanium and germanium fabrication lines. Shared equipment must be purged of germanium contamination before it is used in non-germanium processes, because such contamination is particularly damaging to materials used during conventional IC fabrication. Further, high levels of germanium contamination can be problematic even for strained silicon (SMOS) processes.
Flash devices are particularly sensitive to low level germanium contamination, because Flash technology uses IC structures and processes that are incompatible with germanium. For example, germanium contamination may cause data retention problems for the Flash memory cell. It is nevertheless desirous to use equipment associated with the Flash fabrication line in the manufacture of germanium containing products (e.g., SMOS products).
Thus, there is a need for an efficient process for decontaminating equipment. Further, there is a need for a system and a method which reduces the maintenance time required when a chamber must be purged of germanium contamination. Even further, there is a need for a fabrication equipment which can be utilized in strained silicon processes and can be decontaminated of germanium. Yet further there is a need for a process which decontaminates equipment which is used in germanium and non-germanium processes. Further, there is a need for a decontamination process that allows shared equipment to be used in both a Flash production line and a germanium production line.